FUNCTION: [Summary is not available for the mouse gene. This summary is for the human ortholog.] This gene encodes a member of the GXGD family of aspartic proteases, which are transmembrane proteins with two conserved catalytic motifs localized within the membrane-spanning regions, as well as a member of the signal peptide peptidase-like protease (SPPL) family. This protein is expressed in all major adult human tissues and localizes to late endosomal compartments and lysosomal membranes. A pseudogene of this gene also lies on chromosome 15. [provided by RefSeq, Feb 2012] PHENOTYPE: Mice homozygous for a knock-out allele exhibit decreased immunoglobulin prior to and after immunization and decreased splenic B cells, myeloid dendritic cells, T2 B cells and follicular B cells. Mice homozygous for a hypomorphic allele exhibit similar albeit less severe phenotypes. [provided by MGI curators]